CN112003580A - Power combiner and medical equipment - Google Patents
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- CN112003580A CN112003580A CN202010859099.6A CN202010859099A CN112003580A CN 112003580 A CN112003580 A CN 112003580A CN 202010859099 A CN202010859099 A CN 202010859099A CN 112003580 A CN112003580 A CN 112003580A
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Abstract
The present application relates to a power combiner and a medical device. The power combiner includes: the microwave combiner comprises a microwave combiner, an isolation circuit and at least two microwave branches; the first ports of the at least two microwave branches receive at least two groups of electric signals, and the at least two groups of electric signals are synthesized into a combined signal and output through the second port; the first ends of the isolation circuits are respectively connected to the corresponding microwave branches, and the second ends of the isolation circuits are mutually connected; the isolation circuit comprises an isolation resistor and a resonance capacitor which are connected in series; the impedance characteristic of the first port is adjusted by adjusting the size of the resonance capacitor. According to the power combiner and the medical equipment, the resonance capacitor is connected in series at one side of each isolation resistor close to the common end, namely the side connected with the isolation resistor, and the capacitance value of the resonance capacitor is adjusted, so that the parasitic inductor resonates, and each input second port of the power combiner has good impedance matching and good isolation performance.
Description
Technical Field
The present application relates to the technical field of medical devices, and in particular, to a power combiner and a medical apparatus.
Background
The power combiner is a combining network which combines several kinds of equal or approximately equal small-power signals into one output signal with high power or larger power. The multi-path or less-path synthesis of the synthesizer is adopted according to the output power, and the mode of the synthesis network can be treated in different modes according to different working frequencies of the solid products. The power synthesis technology is mainly adopted and is used in the industries of detection, countermeasure, medical treatment and the like.
The power combiner needs to be provided with a plurality of 50 ohm isolation resistors, and one ends of the isolation resistors need to be connected together. Under high power conditions, the size of the resistor is large, the electrical length of the transmission line connecting the isolation resistors is large, and the matching performance and isolation performance of the power combiner are affected.
Disclosure of Invention
Therefore, it is necessary to provide a power combiner and a medical device for solving the technical problems that the size of a resistor is large under a high power condition, the electrical length of a transmission line connecting a plurality of resistors is large, and the matching performance and the isolation performance of the power combiner are affected.
A power combiner, comprising: the microwave combiner comprises a microwave combiner, an isolation circuit and at least two microwave branches;
one end of at least two microwave branches is connected with one end of the microwave combiner; the other end of the microwave branch is provided with a first port; the other end of the microwave combiner is provided with a second port; the microwave branch and the microwave combiner can be used for combining at least two groups of electric signals into a combined signal and outputting the combined signal through a second port;
the number of the isolation circuits is the same as that of the microwave branches; the first ends of the isolation circuits are respectively connected to the corresponding microwave branches, and the second ends of the isolation circuits are mutually connected;
the isolation circuit comprises an isolation resistor and a resonance capacitor which are connected in series;
the impedance characteristic of the first port is adjusted by adjusting the size of the resonance capacitor.
In one embodiment, the power combiner further comprises an output capacitor;
the output capacitor is connected in parallel to the second port, and the impedance characteristic of the second port is adjusted by adjusting the size of the output capacitor.
In one embodiment, the resistance of the isolation resistor is inversely related to the electrical length of the isolation circuit.
In one embodiment, the power combiner is disposed on a PCB, the PCB includes a top metal layer, a middle metal layer, and a bottom metal layer, a first dielectric layer is disposed between the top metal layer and the middle metal layer, and a second dielectric layer is disposed between the middle metal layer and the bottom metal layer.
In one embodiment, the microwave branch is disposed on the top metal layer.
In one embodiment, the isolation resistors are connected with each other through a resistor connecting line, and the resistor connecting line is arranged on the middle metal layer.
In one embodiment, the impedance of the second port is 50 ohms.
In one embodiment, the isolation resistor has a resistance of 50 ohms.
In one embodiment, the impedance of each of the first ports is 50 ohms.
A medical device comprises the power synthesizer.
According to the power combiner and the medical equipment, the resonance capacitor is connected in series at one side of each isolation resistor close to the common end, namely the side connected with the isolation resistor, and the capacitance value of the resonance capacitor is adjusted, so that the parasitic inductor resonates, and each input second port of the power combiner has good impedance matching and good isolation performance.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a power combiner according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a power combiner according to another embodiment of the present invention;
FIG. 3 is a diagram of an odd-mode analysis of a power combiner according to another embodiment of the present invention;
FIG. 4 is a diagram of an even mode analysis of a power combiner according to another embodiment of the present invention;
fig. 5 is a graph of port standing wave ratio versus frequency for a power combiner according to an embodiment of the invention;
fig. 6 is a graph of port insertion loss versus frequency for a power combiner according to an embodiment of the present invention;
fig. 7 is a graph of port isolation versus frequency for a power combiner in accordance with an embodiment of the present invention.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are set forth in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.
Spatial relational terms, such as "under," "below," "under," "over," and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements or features described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "under" and "under" can encompass both an orientation of above and below. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations) and the spatial descriptors used herein interpreted accordingly.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected to the other element through intervening elements. Further, "connection" in the following embodiments is understood to mean "electrical connection", "communication connection", or the like, if there is a transfer of electrical signals or data between the connected objects.
As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.
The power divider is a device which divides one path of input signal energy into two paths or multiple paths of input signal energy and outputs equal or unequal energy, and can also combine multiple paths of signal energy into one path of output in turn, and at the moment, the power divider can also be called as a power combiner.
At present, a high-power divider/synthesizer is mainly designed under the condition that a source load and a matched load are both real impedance, for example, a source load Z0 and load impedances R1 and R2 are both 50 ohm halving Wilkinson divider/synthesizer. Generally, the power divider adopts two characteristic impedance lines connected in parallel to perform power distribution/synthesis, wherein the two characteristic impedance lines are both 1/4-wavelength transmission lines with 70.7 ohms, and the isolation resistor R is 100 ohms.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a power combiner according to an embodiment of the present invention.
In one embodiment, a power combiner includes: the microwave combiner comprises a microwave combiner, an isolation circuit and at least two microwave branches;
one end of each of the at least two microwave branches is connected with one end of the microwave combiner; the other end of the microwave branch is provided with a first port; the other end of the microwave combiner is provided with a second port; the microwave branch and the microwave combiner can be used for combining the at least two groups of electric signals into a combined signal and outputting the combined signal through a second port;
the number of the isolation circuits is the same as that of the microwave branches; the first ends of the isolation circuits are respectively connected to the corresponding microwave branches, and the second ends of the isolation circuits are mutually connected;
the isolation circuit comprises an isolation resistor R1 and a resonant capacitor C1 which are connected in series;
the first port impedance characteristic is adjusted by adjusting the size of the resonant capacitor C1.
It can be understood that the three low-power electrical signals are respectively input into the microwave branches, and are combined in the microwave combiner after being transmitted by the microwave branches, so as to form high-power energy, and then the high-power energy is output from the second port.
Illustratively, the power splitter is identical in structure to the power combiner, with only differences in the direction of reception, transmission, and output of the signals. It can be understood that, when the power combiner according to the embodiment of the present invention is used as a combiner only, the first port is an input port for receiving multiple groups of low-power electrical signals, and the second port is an output port for outputting a combined high-power combined signal; when the power combiner of the embodiment of the invention is used as a power divider, the second port is an input port for receiving a group of high-power electrical signals, and the first port is an output port for outputting the divided low-power electrical signals.
According to the power combiner, the parasitic inductor is resonated by connecting the resonant capacitor C1 in series at the side of each isolation resistor R1 close to the common end, namely the side connected with the isolation resistor R1, and the capacitance value of the resonant capacitor C1 is adjusted, so that each input second port of the power combiner has good impedance matching and good isolation performance.
Impedance matching (impedance matching) is mainly used on a transmission line, so that the aim of transmitting all high-frequency microwave signals to a load point is fulfilled, and signals are hardly reflected back to a source point, so that the energy efficiency is improved. The signal source internal resistance is equal to the characteristic impedance of the connected transmission line in magnitude and phase, or the characteristic impedance of the transmission line is equal to the characteristic impedance of the connected load impedance in magnitude and phase, which means that the input end or the output end of the transmission line is in an impedance matching state, referred to as impedance matching for short.
Impedance matching refers to achieving a suitable match between a signal source or transmission line and a load. Impedance matching has two main functions, load power adjustment and signal reflection suppression. The first is to adjust the load power, and assuming the excitation source is fixed, the load power is determined by the impedance matching degree of the two. For an ideal pure resistance circuit or a low-frequency circuit, the reactance value caused by the inductance and the capacitance can be basically ignored, the impedance source of the circuit is mainly resistance, and when the impedance matching degree is high, the load power can reach the maximum value. Second, signal reflection is suppressed, and a beam of light is reflected as it travels from the air to the water due to the different light-guiding characteristics of the light and water. Also, reflections can occur during signal transmission if sudden changes in the characteristic impedance occur on the transmission line. The wavelength is inversely proportional to the frequency, and the wavelength of the low frequency signal is much greater than the length of the transmission line, and therefore reflection problems are generally not a concern. In the high-frequency field, when the wavelength of a signal and the length of a transmission line are in the same order, the reflected signal is easy to be mixed with the original signal, and the signal quality is influenced. High-frequency signal reflection can be effectively reduced and eliminated through impedance matching.
The power combiner typically has two or more first ports and only one second port. The port isolation is an important index, which is used to describe the capability of two paths of signals without mutual influence, and is generally required to be over 20 dB. The isolation between the input second ports of the power combiner is usually improved by adding an isolation resistor R1, and the addition of the isolation resistor R1 absorbs the reflected signal between the second ports, thereby increasing the rejection of the signal between the second ports.
It can be understood that the three electrical signals of low power energy are respectively provided by the first power supply V1, the second power supply V2 and the third power supply V3, and are respectively input to the microwave branches, and are combined in the microwave combiner after being transmitted by the microwave branches, so as to form high power energy, and then the high power energy is output from the second port.
Referring to fig. 2, fig. 2 is a schematic structural diagram of a power combiner according to another embodiment of the present invention. Illustratively, the power combiner further comprises an output capacitor C2, wherein the output capacitor C2 is connected in parallel with the second port, and the impedance characteristic of the second port is adjusted by adjusting the size of the output capacitor C2.
It can be understood that the matching characteristic and the isolation characteristic of the synthesizer are affected by the electrical length of the microwave branch, the impedance, the resistance of the isolation resistor R1, the capacitance of the resonant capacitor C1 and the capacitance of the output capacitor C2.
It can be appreciated that for a circuit, the analysis is more complex with a single port input, but a signal can be decomposed into a superposition of odd and even modes, the odd mode analysis is equivalent to adding a ground between two lines, the even mode analysis is two lines in parallel, and one line can be used for circuit and field analysis. The complete circuit is broken down and simplified for analysis. According to the principle of circuit linear addition, the analysis result of the whole circuit can be obtained as soon as the action effects of the odd mode and the even mode are superposed.
Referring to fig. 3, fig. 3 is a diagram illustrating an odd-mode analysis of the power combiner of fig. 2. It will be appreciated that for the odd mode, adding the resonant capacitor C1 resonates out the parasitic inductance LP in the isolation circuit.
Referring to fig. 4, fig. 4 is a diagram illustrating an even mode analysis of the power combiner of fig. 2. It can be understood that, for even mode, the resonant capacitor C1 is added, and the parasitic capacitor CP is connected in series with the resonant capacitor C1, so that the equivalent capacitance CP// C1 of the parasitic capacitor CP is reduced, and the impedance matching is also improved, and the equivalent capacitance CP// C1 is (CP × C1)/(CP + C1). Meanwhile, the output capacitor C2 is connected in parallel to the second port, and the capacitance value of the capacitor C2 is the number of paths of the microwaves multiplied by CP// C1. The matching characteristic of the even mode can be more close to ideal matching by adjusting the electric length and impedance of the microstrip line of the microwave branch circuit to be adaptive.
Referring to fig. 3, the portion of the odd-mode diagram, which is indicated by a dashed line, may be equivalent to the inductor LP 2. The capacitance of C1 is reduced, making the series circuit of C1 and LP capacitive. The inductance of the corresponding equivalent inductance LP2 also becomes large. Choosing an appropriate C1 makes the first port see a real impedance slightly greater than R1. The odd-mode circuit achieves good matching, and the synthesizer has good matching and isolation characteristics.
If the impedance Z1 of the isolation circuit microstrip line is larger, the capacitance of the parasitic capacitor CP is smaller, the inductance LP of the parasitic inductor is larger, the capacitance of the resonant capacitor C1 is relatively smaller, the equivalent capacitance CP// C1 is relatively smaller, and the equivalent inductor LP2 is larger, so that the odd-mode matching characteristic is better. However, the larger the quality factor Q of the series connection of the parasitic capacitor CP and the parasitic resistor LP, the narrower the bandwidth of the power combiner.
The parasitic capacitance generally refers to the capacitance characteristics of the inductor, the resistor, the chip pin, etc. under high frequency. In fact, a capacitor, equivalent to the series connection of a capacitor, an inductor, and a resistor, does not perform very well at low frequencies, while at high frequencies the equivalent value increases, which cannot be ignored, and is taken into account in the calculation. ESL is the equivalent inductance and ESR is the equivalent resistance. Whether it is a resistor, a capacitor, an inductor, a diode, a triode, a MOS tube and an IC, the equivalent capacitance and inductance of the resistor, the capacitor, the inductor and the IC are considered under the condition of high frequency.
In fact, due to the increasing frequency, the influence of parasitic inductance and parasitic capacitance of the lead is increased, and the device is subjected to larger electrical stress (represented by overvoltage and overcurrent burrs). In order to improve the reliability of the system, a 'user-specific' power module (ASPM) is developed, which mounts almost all hardware of a complete machine into a module in the form of a chip, so that the traditional lead connection between components is avoided, and the module achieves perfect optimization through strict and reasonable design in the aspects of heat, electricity and machinery. It is similar to a user-specific integrated circuit (ASIC) in microelectronics. The control software is written into the microprocessor chip in the module, and then the whole module is fixed on the corresponding radiator, thus forming a novel switching power supply device. Therefore, the modularization aims at not only reducing the volume of the whole machine and reducing the volume by using conveniently, but also eliminating the traditional connecting line and reducing the parasitic parameter to the minimum, thereby reducing the electrical stress born by the device to the minimum and improving the reliability of the system.
In another embodiment, the resistance of the isolation resistor R1 is inversely related to the electrical length θ 1 of the isolation circuit. Specifically, the larger the electrical length θ 1 of the microwave branch microstrip line is, the larger the capacitance value of the parasitic capacitance CP is, the relatively larger the equivalent capacitance value CP// C1 is, and the smaller the inductance value of the equivalent inductance LP2 is, at this time, the larger the impedance seen by the first port in the odd-mode circuit is, the worse the Standing Wave Ratio (VSWR) of the odd-mode circuit is; by reducing the resistance of the isolation resistor R1, the impedance value seen by the first port in the odd-mode circuit can return to 50 Ω again, so that the matching characteristic of the odd-mode circuit can reach ideal matching without affecting the matching characteristic of the even-mode circuit.
The Standing Wave Ratio is called as Voltage Standing Wave Ratio, also called VSWR and SWR, and is abbreviated as English Voltage Standard Wave Ratio. It refers to the ratio of the voltage of the antinode of the standing wave to the voltage of the valley, and is also called the standing wave coefficient and standing wave ratio. When the standing-wave ratio is equal to 1, the impedance of the feeder line and the antenna is completely matched, and at the moment, high-frequency energy is radiated by the antenna completely without energy reflection loss; when the standing-wave ratio is infinite, the total reflection is shown, and the energy is not radiated at all. The voltage amplitudes are added to a maximum voltage amplitude V at the same phase of the incident wave and the reflected wavemaxForming an antinode; the voltage amplitude is subtracted to the minimum voltage amplitude at the place where the incident wave and the reflected wave are opposite in phaseVminForming a wave trough. The amplitude values of other points are between the antinodes and the troughs. This resultant wave is called a traveling standing wave. Standing wave ratio is the voltage amplitude V at the antinode of the standing wavemaxWith the voltage amplitude V at the troughmaxThe ratio of. In the standing wave tube method, the standing wave ratio is measured, and then the sound reflection coefficient and the sound absorption coefficient of the sound absorption material can be obtained. The impedance of the radio frequency system needs to be matched, and especially, the voltage standing wave ratio needs to meet certain requirements, because the frequency range is wide when the radio frequency system is used in a broadband, the standing wave ratio can change along with the frequency, and the impedance needs to be matched as much as possible in a wide range.
Quality factor (Q factor), electrical and magnetic quantities. A quality index representing the ratio of the energy stored in an energy storage device (such as an inductance coil, a capacitance and the like) and the energy lost in the resonant circuit per cycle; the Q value of the reactive element is equal to the ratio of its reactance to its equivalent series resistance; the greater the Q value of the element, the better the selectivity of the circuit or network formed by the element. The quality factor of a resonant tank is the ratio of the characteristic impedance of the resonant tank to the tank resistance.
In a series circuit, there are two methods for measuring the quality factor Q of the circuit, i.e. according to the formula Q ═ UL/U0＝UC/U0Measurement, UCAnd ULThe voltages on the capacitor C and the inductance coil L during resonance are respectively; another method is to measure the pass band width of the resonance curve Δ f (f 2-f 1) and then to determine the value of Q f0/(f2-f1) The Q value was obtained. Where f0 is the resonant frequency, f2And f1Is detuned, i.e. the amplitude of the output voltage drops to a maximum
Upper and lower frequency points of multiple times. The larger the Q value, the sharper the curve, the narrower the passband, and the better the circuit selectivity. When the constant voltage source supplies power, the quality factor, the selectivity and the pass band of the circuit are only determined by the parameters of the circuit, and are not related to the signal source.
In another embodiment, the power combiner is disposed on a PCB, the PCB includes a top metal layer, a middle metal layer, and a bottom metal layer, a first dielectric layer is disposed between the top metal layer and the middle metal layer, and a second dielectric layer is disposed between the middle metal layer and the bottom metal layer. It is understood that the PCB is a three-layer PCB.
Illustratively, the PCB board is composed of two dielectric layers and three metal layers positioned above, in the middle and below the two dielectric layers, the top metal layer is a microstrip multi-path power distribution network, the middle metal layer is a grounding metal layer, and the bottom metal layer comprises a microstrip isolation network and an isolation resistor. The top power distribution network and the bottom isolation network are connected by a metalized via located at a quarter wavelength from a common point of the top power distribution network, wherein the metalized via crossing the intermediate ground metal layer is not contiguous with the intermediate ground metal layer. The bottom layer isolation network consists of microstrip lines and isolation resistors, wherein one end of each microstrip line is connected to a common point, the other end of each microstrip line is connected with each upper layer microstrip line, each section of microstrip line consists of two sections of microstrip lines with different widths and one quarter of wavelengths, one end of each isolation resistor is connected to the joint of the two sections of microstrip lines with different widths, and the other end of each isolation resistor is connected to the middle metal layer through a metalized through hole.
In another embodiment, the microwave branch and the microwave combiner are disposed on the top metal layer.
In another embodiment, the isolation resistors R1 are connected by resistive connecting lines disposed in the middle metal layer.
In another embodiment, the isolation resistor R1 has a resistance of 50 ohms. It is understood that when the electrical length θ 1 of the resistor connecting line is relatively small or the requirement on the isolation index of the synthesizer is not high, the isolation resistor R1 may be a 50 ohm resistor. When the electrical length θ 1 of the resistor connecting line is relatively large or the requirement on the isolation index of the synthesizer is high, the resistance value of the isolation resistor R1 needs to be less than 50 ohms, and the resistance value is affected by the electrical length of the resistor connecting line.
In another embodiment, the characteristic impedance Z2 of the microstrip line of each microwave branch is greater than or equal to
Ohm, electrical length θ 2 is equal to or less than 90 degrees. It can be understood that when the characteristic impedance and the electrical length of the microstrip line of the microwave branch are within this range, the matching and isolation performance of the power combiner can be optimized by adjusting the capacitance value of the resonant capacitor C1 and the resistance value of the isolation resistor R1.
In another embodiment, the impedance of each first port is 50 ohms.
In another embodiment, the impedance of the second port is 50 ohms.
In another embodiment, the number of the first ports is 3, and the number of the microwave transmission branches is 3. It is understood that in other embodiments, the combination of the energy paths may be determined according to actual conditions.
Referring to fig. 5 to 7, fig. 5 is a graph of a port standing-wave ratio of a power combiner according to an embodiment of the present invention as a function of frequency, fig. 6 is a graph of a port insertion loss of a power combiner according to an embodiment of the present invention as a function of frequency, and fig. 7 is a graph of a port isolation of a power combiner according to an embodiment of the present invention as a function of frequency. Wherein, the port 1 corresponds to an output port of the synthesizer, the ports 2,3, 4 correspond to input ports of the synthesizer, S (2,3) is a condition that the port isolation between the first input port and the second input port varies with frequency, S (2,4) is a condition that the port isolation between the first input port and the third input port varies with frequency, S (3,4) is a condition that the port isolation between the second input port and the third input port varies with frequency, S (1,1) represents a condition that the standing wave ratio of the output port varies with frequency, S (2,2) represents a condition that the standing wave ratio of the first input port varies with frequency, S (3,3) represents a condition that the standing wave ratio of the second input port varies with frequency, S (4,4) represents a condition that the standing wave ratio of the third input port varies with frequency, S (2,1) represents a condition that the port insertion loss from the first input port to the output port varies with frequency, s (3,1) represents a case where the port insertion loss from the second input port to the output port varies with frequency, and S (4,1) represents a case where the port insertion loss from the third input port to the output port varies with frequency. The test result shows that the reflection coefficient of each port of the synthesizer is lower than-30 dB; the isolation between input ports is lower than-36 dB; the loss of the synthesizer is below 0.2 dB.
The invention also discloses medical equipment which comprises the power synthesizer, and the production cost of the medical equipment can be saved by using the power synthesizer.
A magnetic resonance imaging apparatus is a type of tomographic imaging that obtains electromagnetic signals from a human body using a magnetic resonance phenomenon and reconstructs human body information. The magnetic resonance imaging apparatus applies a radio frequency pulse of a certain specific frequency to a human body in a static magnetic field to excite hydrogen protons in the human body to generate a magnetic resonance phenomenon. After the stopping pulse, the protons produce magnetic resonance signals during relaxation. And acquiring a corresponding magnetic resonance signal, and performing image reconstruction on the magnetic resonance signal to obtain a medical image. Magnetic resonance imaging (MR) is a very powerful imaging method. The technology can obtain high-contrast clear images of the interior of a sample/tissue under the conditions of no damage and no ionizing radiation, and is widely applied to various fields, particularly medical diagnosis. Compared with other auxiliary imaging examination means, the nuclear magnetic resonance imaging examination method has the advantages of multiple imaging parameters, high scanning speed, high tissue resolution, clearer image and the like. Can find early lesions, and is a tool for early screening of tumors, heart diseases and cerebrovascular diseases at present.
The power combiner is an important component in the magnetic resonance imaging equipment, and is commonly used in many high-power amplifiers to combine the power generated by a plurality of low-power devices into the required high power.
According to the power combiner and the medical equipment, the parasitic inductance is resonated in a mode that the isolation resistors are connected with the resonance capacitor in series at one side close to the common end, namely the side connected with the isolation resistors is connected with the output capacitor in parallel at the second port, and each input second port of the power combiner has good impedance matching and good isolation performance.
In the description herein, references to the description of "some embodiments," "other embodiments," "desired embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, a schematic description of the above terminology may not necessarily refer to the same embodiment or example.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A power combiner, comprising: the microwave combiner comprises a microwave combiner, an isolation circuit and at least two microwave branches;
one end of at least two microwave branches is connected with one end of the microwave combiner; the other end of the microwave branch is provided with a first port; the other end of the microwave combiner is provided with a second port; the microwave branch and the microwave combiner can be used for combining at least two groups of electric signals into a combined signal and outputting the combined signal through a second port;
the number of the isolation circuits is the same as that of the microwave branches; the first ends of the isolation circuits are respectively connected to the corresponding microwave branches, and the second ends of the isolation circuits are mutually connected;
the isolation circuit comprises an isolation resistor and a resonance capacitor which are connected in series;
the impedance characteristic of the first port is adjusted by adjusting the size of the resonance capacitor.
2. The power combiner of claim 1, further comprising an output capacitor;
the output capacitor is connected in parallel to the second port, and the impedance characteristic of the second port is adjusted by adjusting the size of the output capacitor.
3. The power combiner of claim 1, wherein a resistance of the isolation resistor is inversely related to an electrical length of the isolation circuit.
4. The power combiner of claim 1, wherein the power combiner is disposed on a PCB board, the PCB board comprising a top metal layer, a middle metal layer, and a bottom metal layer, wherein a first dielectric layer is disposed between the top metal layer and the middle metal layer, and wherein a second dielectric layer is disposed between the middle metal layer and the bottom metal layer.
5. The power combiner of claim 4, wherein the microwave branch is disposed at the top metal layer.
6. The power combiner of claim 4, wherein the isolation resistors are connected by resistive connecting lines disposed in the intermediate metal layer.
7. A power combiner as recited in claim 1, wherein said second port has an impedance of 50 ohms.
8. The power combiner of claim 1, wherein the isolation resistor has a resistance of 50 ohms.
9. A power combiner as recited in claim 1, wherein the impedance of each of said first ports is 50 ohms.
10. A medical device comprising a power combiner as claimed in any one of claims 1 to 9.
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| CN202010859099.6A CN112003580A (en) | 2020-08-24 | 2020-08-24 | Power combiner and medical equipment |
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| CN202010859099.6A CN112003580A (en) | 2020-08-24 | 2020-08-24 | Power combiner and medical equipment |
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| CN112003580A true CN112003580A (en) | 2020-11-27 |
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| CN113134155A (en) * | 2021-04-06 | 2021-07-20 | 武汉光燚激光科技有限公司 | Skin therapeutic instrument by transdermal diffusion |
| CN117914278A (en) * | 2024-03-19 | 2024-04-19 | 南京正銮电子科技有限公司 | High-power synthesizer |
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Address after: 201807 2258 Chengbei Road, Jiading District, Shanghai Applicant after: Shanghai Lianying Medical Technology Co., Ltd Address before: 201807 2258 Chengbei Road, Jiading District, Shanghai Applicant before: SHANGHAI UNITED IMAGING HEALTHCARE Co.,Ltd. |